Treesearch

Water is the most important and most common chemical used in plant nurseries. It is also the most dangerous chemical used. Insufficient water, excessive water, and poorly timed irrigation can all lead to poor-quality crops and unacceptable mortality. Anticipated future declines of water availability, higher costs to use it, and continuing concerns about irrigation runoff harming the environment also spur interest in making more efficient use of water in nurseries. This article discusses water management in container nurseries and its influence on weeds, insects, and diseases. It also...

We found that different spectra, provided by light-emitting diodes or a fluorescent lamp, caused different photomorphological responses depending on tree seedling type (coniferous or broad-leaved), species, seedling development stage, and seedling fraction (shoot or root). For two conifers (Picea abies and Pinus sylvestris) soon after germination (≤40 days), more seedling growth was related to a lower ratio of red-to-far-red (R:FR) light. As growth continued to 120 days, spectra with a greater complement of blue light yielded more growth. Roots showed more plasticity to light spectra than...

The goal of this study was to discover the nature and intensity of the interaction between an exotic invader Ailanthus altissima (Mill.) Swingle and its coexisting native Robinia pseudoacacia L. and consider management implications. The study occurred in the Mid-Appalachian region of the eastern United States. Ailanthus altissima can have a strong negative influence on community diversity and succession due to its allelopathic nature while R. pseudoacacia can have a positive effect on community diversity and succession because of its ability to fix nitrogen. How these trees interact and...

Two new species of egg parasitoids, Oobius saimaensis Yao and Mottern new species and Oobius fleischeri Yao and Duan new species (Hymenoptera: Encyrtidae), are described from eggs of Agrilus fleischeri Obenberger, 1925 (Coleoptera: Buprestidae). Agrilus fleischeri is a phloemfeeding woodborer of poplar (Populus Linnaeus; Salicaceae) in northeastern China. These two species can be distinguished morphologically as O. fleischeri has five tarsomeres and O. saimaensis has four tarsomeres. Although O. saimaensis is morphologically similar to its sympatric congener O. agrili Zhang and Hang, 2005,...

Overstory forest structure responds to terrain‐related abiotic factors and to biotic interactions among overstory and understory plants. Unlike species abundance, tree height, biomass, and leaf area in many regions have been poorly quantified in relation to terrain‐driven environmental gradients. In addition, the magnitude of understory influences on overstory structure has been poorly characterized for many forest systems. Our primary goal was to identify relationships between terrain (elevation, convexity, exposure), evergreen understory, and overstory structure (height, aboveground...

Southern Appalachian riparian forests have undergone changes in composition and function from invasive pathogens and pests. Castanea dentata mortality in the 1930s from chestnut blight (Cryphonectria parasitica) and Tsuga canadensis mortality in the 2000s from the hemlock woolly adelgid (Adelges tsugae) have led to the expansion and increased growth of Rhododendron maximum, an evergreen subcanopy shrub. A better understanding of seed bank characteristics and the various abiotic and biotic factors that affect the seed bank may be useful in determining the restoration potential of forest...

Proceedings from the 2014 IUFRO Joint Conference: Genetics of five-needle pines, rusts of forest trees, and Strobusphere in Fort Collins, Colorado. The published proceedings include 91 papers pertaining to research conducted on the genetics and pathology of five-needle pines and rusts of forest trees. Topic areas are: ecology and climate change, common garden genetics, genomic resources, rust resistance, and rust biology, ecology, and management.

The use of raw boron minerals (i.e. tincalconite, colemanite, and ulexite) was evaluated to increase the fire performance of wood plastic composites (WPCs) in comparison with commercially available fire retardants (FRs). Cone calorimetry and limited oxygen index tests were performed to evaluate the fire properties of WPC specimens. Artificial weathering and 3-point bending tests were also performed on the test specimens loadedwith the highest loading level of FRs. The most important decrease in theheat release rate values was 42% and 40% in the magnesium hydroxide- and colemanite-added...

Although the aggregate U.S. housing market was mixed in December, both new single-family (SF) sales and starts were revised substantially downward. Other housing data appear to have flat-lined on a month-over-month basis. Regionally, data were mixed across all sectors. New SF construction and remodeling spending remain positive, increasing at an incremental pace.

Tribal communities in the Pacific Northwest of the United States of America (USA) have long-standing relationships to ancestral lands now managed by federal land management agencies. In recent decades, federal and state governments have increasingly recognized tribal rights to resources on public lands and to participate in their management. In support of a new planning initiative to promote sustainable land management, we reviewed scientific publications to examine relationships between tribal social-ecological systems and public lands in the region. We identified key ecocultural resources...